This invention relates in general to vehicle disc brake assemblies and in particular to an improved dust boot seal adapted for use in such vehicle disc brake assemblies.
Most vehicles are equipped with a brake system for slowing or stopping movement of the vehicle in a controlled manner. A typical brake system for an automobile or light truck includes a disc brake assembly for each of the front wheels and either a drum brake assembly or a disc brake assembly for each of the rear wheels. The brake assemblies are actuated by hydraulic or pneumatic pressure generated when an operator of the vehicle depresses a brake pedal. The structures of these drum brake assemblies and disc brake assemblies, as well as the actuators therefore, are well known in the art.
A typical disc brake assembly includes a rotor, which is secured to the wheel of the vehicle for rotation therewith. A caliper assembly is supported on pins, which are secured to an anchor bracket. The anchor bracket is secured to a non-rotatable component of the vehicle, such as the vehicle frame. The caliper assembly includes a pair of brake shoes, located on opposite sides of the rotor. The brake shoes are operatively connected to one or more hydraulically actuated pistons for movement between a non-braking position, wherein they are spaced apart from opposed axial sides or braking surfaces of the rotor, and a braking position, wherein they are moved into frictional engagement with the braking surfaces of the rotor. When the operator of the vehicle depresses the brake pedal, the piston urges the brake shoes from the non-braking position to the braking position causing their frictional engagement with the opposed braking surfaces of the rotor, thereby slowing or stopping rotation of the associated wheel of the vehicle.
A typical disc brake assembly also includes a dust boot seal. The dust boot seal is formed from a flexible material and has a first end, which engages an outboard end of the cylinder. A second end of the dust boot seal engages an annular groove formed in an outer side wall of the piston. A plurality of flexible convolutions is provided in the dust boot seal between the first and second ends thereof. The dust boot seal is provided to prevent water, dirt, and other contaminants from entering into the recess between the cylinder and the piston.